The present invention relates to an electrode clamping device with an electrode holding unit for electroremelting plants equipped with a mold and an electrode carrying device, in which at least one adjustment device is arranged for adjusting the angular position of the electrode holding member and electrode.
Such electrode clamping devices for electroslag remelting plants are known for example from German Offenlegungsschrift No. 1,816,450 and German Auslegeschrift No. 21 34 089. The adjustment devices in these cases are in the form of a cardan or universal joint in which the electrode, on account of its center of gravity and the force due to gravity, can align itself to such an extent that, for example, the effect of an obliquely welded-on clamping end (stub) is largely compensated. By maintaining appropriate frictional conditions within the cardan joint, it is possible to make the electrode adjustable only externally. With the known devices it is however not possible, if there are variations in the electrode position within the mold, to influence selectively or purposefully the electrode plant or effect remedial measures. When remelting an individual consumable electrode according to the electroslag remelting process within a mold, it is however desirable to arrange the mold and electrode as concentrically as possible so that the slag bath is as symmetrical as possible on all sides. The concentricity or axial symmetry is extremely important as regards the melting process, the heat profile in the slag bath and molten metal, and also as regards the solidification conditions of the metallic melt.
The X-Y-adjustment devices disclosed in German Offenlegungsschrift No. 25 12 169 and German Offenlegungschrift No. 27 31 227 relate to the horizontal movement of the consumable electrode during the remelting operation. These adjustment devices are associated with geared motors having spindles in the X and Y directions. The electrodes are suspended in horizontally movable carriages. However, the electrode axis can only be displaced parallel to itself, and an angular adjustment of the electrode axis with respect to the reference point is not possible. For this reason these adjustment devices cannot be used in vacuum electric arc furnaces, since the electrode rod there present and located within a sealed duct prevents any parallel movement of the electrode.
If there is too small a distance between the electrode and mold wall on one side, there is the danger that in the case of electric arc furnaces the arc, or in the case of electroslag remelting furnaces the current path, will take the shortest route between the electrode and mold wall. In this case a localized melting of the mold wall may occur, and if the mold is cooled by water the danger of the steam explosion cannot be excluded.
The ability to adjust the electrode is particularly important when replacing an electrode, in which a further electrode must be mounted in the shortest possible time in its remelting position once the previous electrode has been consumed. For the aforementioned reasons it is essential when mounting the subsequent electrode to carry out position corrections by rotating the electrode axis. This could not be done in a selective manner however with the previously known devices.